Autor(es)

Cantane, D. A. ^[1] ; Oliveira, F. E. R. ^[1] ; Santos, S. F. ^[2] ; Lima, F. H. B. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Abc, Ctr Engn Modelagem & Ciencias Sociais Aplicada, BR-09210170 Santo Andre, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: APPLIED CATALYSIS B-ENVIRONMENTAL; v. 136, p. 351-360, JUN 5 2013.
• Citações Web of Science: 56

Resumo

Pt-based hollow nanoparticles were investigated as electrocatalysts for the oxygen reduction reaction (ORR) in acid electrolyte. The electrocatalysts were synthesized via Ni or Co diffusion/dissolution, induced by the vacancy-mediated Kirkendall effect, during electrochemical potential cycling of Ni@Pt and Co@Pt core-shell nanoparticles in acid media. The nanoparticles were characterized by high resolution transmission electron microscopy, in situ X-ray absorption spectroscopy and X-ray diffraction measurements. The results show substantial differences in nanoparticle structure/composition and in the activity for the ORR, depending on the nature of the non-noble metal in the nanoparticle core. The Pt hollow nanostructures showed higher specific catalytic activity than that of the state-of-the-art Pt/C electrocatalyst. This was attributed to three main effects: (i) hollow-induced lattice contraction in the multilayer Pt shells, (ii) mismatch-induced lattice contraction of the thick Pt shell by the remaining Ni or Co atoms and (iii) a ligand effect, due to the electronic interaction of Pt with the remaining Ni or Co atoms in the Pt multilayers of the hollow structure. These three effects caused a Pt d-band center down-shift, which decreased the adsorption strength of oxygenated reaction intermediates and spectators, thus increasing the ORR rate. (C) 2013 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 11/50727-9 - Desenvolvimento de sistemas para produção de hidrogênio e para geração e utilização de energia eletro-química
• Beneficiário: Ernesto Rafael Gonzalez
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 09/07629-6 - Eletrocatálise IV: aspectos fundamentais e aplicados dos processos eletrocatalíticos, bio-eletrocatálise e instabilidades cinéticas
• Beneficiário: Edson Antonio Ticianelli
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Temático
• Processo FAPESP: 09/11073-3 - Investigação do mecanismo de eletro-oxidação do etanol em nanopartículas metálicas.
• Beneficiário: Daniel Augusto Cantane
• Modalidade de apoio: Bolsas no Brasil - Doutorado